Multiple-roll rolling mill for strip material

ABSTRACT

The present invention relates to a cluster mill for strip material, having working rolls ( 1, 2 ), which are supported, via possibly existing intermediate rolls ( 4, 5 ), on backup rolls ( 6, 7, 8, 9-16   b ), which are each rotatably mounted jointly on a support axle ( 17, 18, 19, 20 ), divided into at least three longitudinal sections (L 1 , L 2 , L 3 ), and having at least one adjustment device, which is assigned to at least one of the support axles ( 18 ) and includes actuator drives ( 35, 36, 37 ), each one of which is assigned to one of the longitudinal sections (L 1 , L 2 , L 3 ) of the support axle ( 18 ) at each case and, via a group (G 1 , G 2 , G 3 ) of actuators ( 24, 25, 26; 27, 28; 29, 30, 31 ), which are coupled to one another via a coupling element ( 32, 33, 34 ) in regard to their movement in relation to the support axle ( 18 ), apply a force, directed transversely to the longitudinal direction of the support axle ( 18 ), to the respective longitudinal section (L 1 , L 2 , L 3 ) to correct the roll gap ( 3 ) between the working rolls ( 1, 2 ).

[0001] The present invention relates to a cluster mill for strip material, in particular steel strips, having working rolls which are supported on the stand of the rolling mill via backup rolls. In such cluster mills, the working rolls are typically supported via intermediate rolls positioned between the backup rolls and the respective working roll. The backup rolls are typically mounted in this case at regular intervals along the working or intermediate roll on a support axle extending parallel to the rotational axis of these rolls.

[0002] Cluster mills of the type described above are typically equipped with adjustment devices for influencing the geometry of the roll gap. The roll gap geometry has a direct influence on the shape of the rolled material.

[0003] A roll support device for correcting the roll gap of a cluster mill is known, for example, from German Patent Application 41 31 571 A1. In this known device, actuators, which are displaceably guided in the stand of the rolling mill transversely to the longitudinal extension of the support axle, engage the support axle in the free spaces present between the backup rolls at each case. The actuators are divided in this case into two groups of equal number in such a way that the first group is assigned to a longitudinal section which corresponds to the first half of the longitudinal extension of the support axle, while the other group is assigned to the longitudinal section corresponding to the second half of the support axle.

[0004] The actuators of the two groups are each connected jointly in an articulated way to a coupling element. The two coupling elements extend essentially parallel to the support axle and their ends assigned to the ends of the support axle are mounted in an articulated way on the stand of the rolling mill. In contrast, the other ends of the coupling elements, which are assigned to the middle of the support axle, are connected to a shared actuator drive, which pivots the coupling elements via an actuator cylinder, which is hydraulically operated and movable transversely to the support axle, and in this way cause adjustment of the actuators and therefore deflection of the support axle. This deflection is transmitted to the working roll via the backup rolls mounted on the support axle, so that a corresponding shape of the roll gap results.

[0005] The advantage of the device known from German Patent Application 41 31 571 A1 is that the desired different changes in position of the actuators, and correspondingly the setting of the roll gap, may be performed using only one single actuator drive. The outlay for apparatus and costs for the supporting device is reduced to a minimum in this way. However, it is disadvantageous that only a curve of the roll gap may be set in which the height of the roll gap changes linearly from its outer ends in the direction toward the middle of the roll gap. Roll gap geometries deviating from the linear curve may not be implemented due to the fixed coupling of the movement of the actuators of both groups. This restricted adjustability has been shown to be disadvantageous in particular in cold rolling of steel strips, in which, among other things, to compensate the deformations of the working rolls caused by the rolling forces, a non-linear curve of the roll gap opening is necessary for producing a product having a uniform extension.

[0006] In order to allow free adjustability of the roll gap, the transition has been made to assigning each individual actuator its own actuator drive for this purpose. In this case, there is no longer mechanical coupling between the actuators through a coupling element, so that any shape of the roll gap necessary in practice may be set through a corresponding setting of each individual actuator drive. However, the high outlay for costs and control which is required for manufacturing and operating the actuator drives is disadvantageous in this case.

[0007] On the basis of the related art described above, the object of the present invention is to provide a cluster mill in which extensive adjustability of the roll gap is made possible through a cost-effective supporting device.

[0008] This object is achieved by a cluster mill for strip material which is equipped with working rolls, supported via possibly existing intermediate rolls on backup rolls, which are each jointly rotatably mounted on a support axle divided into at least three longitudinal sections, and is equipped with at least one actuating device, which is assigned to at least one of the support axles and includes actuator drives, each one of which is assigned to one of the longitudinal sections of the supporting axle, and has a force directed transversely to the longitudinal direction of the support axle applied to the respective longitudinal section via a group of actuators coupled to one another via a coupling element in regard to their movement relative to the support axle to correct the roll gap between the working rolls.

[0009] In a cluster mill stand according to the present invention, the support axle is divided into at least three longitudinal sections, each of these longitudinal sections being assigned its own actuator drive. This actuator drive exerts the force necessary for influencing the roll gap geometry on the support axle via a group of actuators. Each of these groups includes two or more actuators in this case, whose movements transverse to the support axle are mechanically coupled to one another via a coupling element. Since, at the same time, no mechanical coupling is provided between the groups, each group of actuators may be adjusted independently of the other groups by the respective actuator drive. In this way, multiple different roll gap geometries may be set as a function of the number and distribution of the actuator groups, without separate control of each individual actuator by its own actuator drive being necessary for this purpose, as is still the case in the related art.

[0010] The present invention thus allows significantly reduced costs relative to typical rolling mills, which allow largely free adjustability of the roll gap, and, in relation to rolling mills having permanently specified adjustability of the roll gap, a significantly increased multiplicity of adjustment possibilities for targeted setting of an optimum roll gap for practical operation. It has been shown that the adjustability of the roll gap geometry ensured through the present invention is sufficient for the great majority of requirements occurring in practice.

[0011] Since the roll gap geometry required in practical operation typically has a symmetrical curve in the longitudinal extension, it is favorable if the support axle is divided into longitudinal sections arranged symmetrically starting from the middle of the longitudinal extension of the support axle. In this context, it is advantageous if there is a longitudinal section positioned centrally at the middle of the longitudinal extension of the support axle and the actuator drive assigned to this longitudinal section applies the force, generated by the actuator drive, to the coupling element of the group of actuators assigned to this longitudinal section at a location positioned in alignment with the middle of the longitudinal extension.

[0012] A further embodiment of the present invention, which is also advantageous for specific applications, is characterized in that, in at least one group of actuators, which are coupled to one another, the assigned actuator drive applies the force, which is generated by the actuator drive, to the coupling element at a location offset in relation to the middle of the longitudinal extension of the longitudinal section assigned to the group. This introduction of the adjustment forces into the respective coupling element has been shown to be expedient in particular in those coupling elements via which the respective actuators of the groups which are assigned to the two longitudinal sections positioned at the outer ends of the support axle are connected to one another, if these coupling elements are each mounted in an articulated way on the stand of the rolling mill. Due to the lever principle, a curve of the deflection in the affected longitudinal section of the support axle which always proceeds from an identical starting position at the end of the support axle automatically results through the mounting of the respective coupling elements of the groups of actuators positioned on both ends of the support axle. Proceeding from this starting position, the degree of the change in position of the support axle achieved during adjustment of the actuators increases in the direction toward the middle of the axle, so that a deflection curve of the support roll which counteracts the deformation of the working roll during rolling operation is generated in the edge regions.

[0013] As in the related art, it is also favorable in the context of the present invention if the support elements are positioned at regular intervals along the support axle. In this way, uniform support of the working roll is also achieved.

[0014] In the following, the present invention is described in more detail with reference to a drawing illustrating an exemplary embodiment.

[0015]FIG. 1 shows a roll support device in a frontal view;

[0016]FIG. 2 shows a detail of a cluster mill equipped with the roll support device shown in FIG. 1 in section along line X-X in FIG. 1;

[0017]FIG. 3 shows the cluster mill in a section along line Y-Y in FIG. 2.

[0018] Cluster mill W has work rolls 1, 2. A roll gap 3 is implemented between work rolls 1, 2, in which a steel strip S is cold rolled, for example.

[0019] Work rolls 1, 2 are each supported via intermediate rolls 4, 5 on backup rolls 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 a and 16 b, nine of which are at each case rotatably mounted at regular intervals a on support axle 17, 18, 19, 20, respectively. In FIG. 2, of the nine backup rolls mounted on each support axle 17, 18, 19, 20, only backup rolls 6, 7, 8, 13, which are visible in accordance with section line X-X indicated in FIG. 1, are illustrated, while in FIG. 3, all nine backup rolls 9 to 16 b mounted on support axle 18 are shown for support axle 18. Of course, further backup rolls may be present, which are mounted in the same way on support axles 17 to 20.

[0020] As may be seen in FIGS. 2 and 3, a thrust element 21 engages on support axle 18 in the spaces existing at each case, between backup rolls 9 to 16 b. Thrust elements 21 are displaceably mounted in the horizontal direction on stand 22 of rolling mill W and are coupled via a wedge drives 23 to vertically movable, rod-shaped actuators 24, 25, 26, 27, 28, 29, 30, 31, which are guided in stand 22. Via wedge drive 23, a movement of actuators 24 to 31 in the vertical direction is converted into a horizontal movement of respective thrust element 21 assigned to respective actuator 24 to 31.

[0021] Actuators 24 to 31 are collected into groups G1, G2, G3, beginning at one end of support axle 18, first group G1 being assigned first three actuators 24, 25, 26, second group G2 being assigned actuators 27, 28, and third group G3 being assigned actuators 29, 30, 31. Each group G1, G2, G3 is in turn assigned a longitudinal section L1, L2, L3 of support axle 18. Longitudinal sections L1, L2, L3 directly border one another and are aligned symmetrically to middle M of support axle 18 in relation to the longitudinal extension of support axle 18, the length of external longitudinal sections L1, L3 being greater than the length of longitudinal section L2 positioned between these longitudinal sections L1, L3.

[0022] The respective ends of actuators 24, 25, 26, belonging to group G1, which face away from respective wedge drives 23 are coupled in an articulated way to a coupling element 32, whose axis extends essentially parallel to support axle 18 and whose end assigned to the end of support axle 18 is mounted in an articulated way on stand 22 of the rolling mill W. In the same way, actuators 29, 30, 31 of group G3, assigned to the other end of support axle 18, are jointly coupled to a coupling element 33, whose end assigned to the affected end of support axle 18 is also mounted in an articulated way on stand 22 of rolling mill W. Actuators 27, 28 of central group G2, in contrast, are jointly coupled to a coupling element 34 which is not supported on stand 22.

[0023] On the respective ends of coupling elements 32, 34 opposite to the articulated support on stand 22, each of these coupling elements 32, 34 is connected in an articulated way to a piston rod of a hydraulically operating actuator drive 35, 37. Coupling element 33 of central group G2 of both actuators 27, 28, in contrast, is connected to the piston rod of a hydraulic actuator drive 36. The piston rod of actuator drive 36 is positioned centrally to the longitudinal extension of support axle 18, so that the force generated by actuator drive 36 is distributed essentially uniformly onto actuators 27, 28. In contrast, the force generated by actuator drives 35, 37 is, in accordance with the lever principle, transmitted non-uniformly to actuators 24 to 26 and 29 to 31, respectively, of the respective groups G1 and G3.

[0024] Thrust elements 21, wedge drives 23, actuators 24 to 31, coupling elements 32, 33, 34, and actuator drives 35, 36, 37, are part of the adjustment device for adjusting the support forces applied by backup rolls 9 to 16 b. For adjustment of backup rolls 6, 7, 8, which are positioned on support axles 17, 19, 20, they may be provided their own adjustment devices of the same type, which are not described in detail here.

[0025] During setting of the geometry of roll gap 3, actuator drives 35, 36, 37 exert adjustment forces separately from one another on respective groups G1, G2, G3 of actuators 24 to 31 assigned to them. These adjustment forces are converted, via wedge drives 23, into deflection forces, which act on the support axle 18 in an alignment essentially transverse to support axle 18. Support axle 18 deforms in accordance with the different distributions of the forces applied. This deformation is transmitted to upper working roll 1 via intermediate rolls 4, 5, so that as a result the roll gap geometry is directly influenced by the adjustment of actuator drives 35, 36, 37.

[0026] List of Reference Numbers

[0027]1, 2 working rolls

[0028]3 roll gap

[0029]4, 5 intermediate rolls

[0030]6 to 16 b backup rolls

[0031]17, 18, 19, 20 support axles

[0032]21 thrust element

[0033]22 stand of rolling mill W

[0034]23 wedge drive

[0035]24 to 31 actuators

[0036]32, 33, 34 coupling elements

[0037]35, 36, 37 actuator drives

[0038] a axial interval between each two backup rolls

[0039] G1, G2, G3 groups of actuators 24 to 30

[0040] L1, L2, L3 longitudinal sections of support axle 18

[0041] M middle of support axle 18

[0042] S steel strip

[0043] W cluster mill 

1. A cluster mill for strip material having work rolls (1, 2), which are supported, via possibly existing intermediate rolls (4, 5), on backup rolls (6, 7, 8, 9-16 b), which are each rotatably mounted jointly on a support axle (17, 18, 19, 20), divided into at least three longitudinal sections (L1, L2, L3), and having at least one actuating device, which is assigned to at least one of the support axles (18) and includes actuator drives (35, 36, 37), each one of which is assigned to one of the longitudinal sections (L1, L2, L3) of the support axle (18) and has a force directed transversely to the longitudinal direction of the support axle (18) applied to the respective longitudinal section (L1, L2, L3) via a group (G1, G2, G3) of actuators (24, 25, 26; 27, 28; 29, 30, 31), which are coupled to one another via a coupling element (32, 33, 34) in regard to their movement in relation to the support axle (18) to correct the roll gap (3) between the working rolls (1, 2).
 2. The cluster mill according to claim 1, characterized in that the support axle (18) is divided into longitudinal sections (L1, L2, L3), which are symmetrically arranged starting from the middle of the longitudinal extension of the support axle (18).
 3. The cluster mill according to claim 2, characterized in that there is a longitudinal section (L2), which is positioned in alignment to the middle (M) of the longitudinal extension of the support axle (18), and the actuator drive (36) assigned to this longitudinal section (L2) applies the force, generated by the actuator drive (36), to the coupling element (33) of the group (G2) of actuators (27, 28) assigned to this longitudinal section (L2) at a location positioned in alignment to the middle of the longitudinal extension.
 4. The cluster mill according to one of the preceding claims, characterized in that, in at least one group (G1, G3) of actuators (24, 25, 27; 29, 30, 31), which are coupled to one another, the assigned actuator drive (35, 37) applies the force, generated by the actuator drive (35, 37), to the coupling element (32, 34) at a location offset in relation to the middle of the longitudinal extension of the longitudinal section (L1, L3) assigned to the group (G1, G3).
 5. The cluster mill according to one of the preceding claims, characterized in that at least the coupling elements (32, 34), via which the respective actuators of the groups (G1, G3) which are assigned to the longitudinal sections (L1, L3) positioned at the outer ends of the support axle (18) are connected to one another, are mounted on the stand (22) of the rolling mill (W) in an articulated way.
 6. The cluster mill according to one of the preceding claims, characterized in that the backup rolls (6, 7, 8, 9-16 b) are positioned at regular intervals (a) along the support axle (18).
 7. The cluster mill according to one of the preceding claims, characterized in that the actuator drives (33, 34, 35) operate hydraulically. 